There is a sort of limit to the areas where pure reason can reach as Kant showed. And he also saw that when human reason attempts to pursue areas beyond what is beyond the possibilities of experience, that it comes up with self contradictions. Furthermore he saw a sort of psychological insight from that observation. That people that do attempt to probe into areas beyond the possibility of experience tend to go insane. So you can see why in the Litvak Yeshiva world, interest in mysticism is usually discouraged.
[However, that does not mean that I distrust anyone with spiritual insight. For example, the Gra himself and from the middle ages, Rav Avraham Abulafia. Rather, it is just not something to do unless one is really on that level. Plus, there is the problem of discernment.]
The kind of approach that I take towards issues of faith is more or less this. That moral principles are universals. [I.e., laws or characteristics. Moral laws are universals since they are laws that things have in common. Like: it is wrong to torture people for the fun of it. That is a law that applies to people, and they have in common.] And some universals are known or can be discerned by reason. Also morality is objective and not reducible to physical laws. See G.E. Moore and Prichard.
